The present invention relates to voltage management, and in particular, to circuits and methods for dynamic voltage management.
Portable applications such as Personal Digital Assistants (PDAs), cell phones, and portable media players (PMPs) often operate from battery power. These applications try to conserve power when possible to increase the time between re-charging of the battery. Many portable devices implement standby and sleep modes to conserve power when the devices are not actively being used. For example, a cellular phone may switch into a standby mode when the user has not opened the phone to make a call for more than a minute. In standby mode, the cellular phone may turn off or disable all unnecessary electronics such that only a standby circuit is active. This limited operating condition may reduce power consumption and therefore may extend the time between re-charging of the battery.
Electronic devices may also utilize a sleep mode. The sleep mode may disable all unnecessary electronics as well. Sleep mode for these devices may utilize a small portion of current to power a circuit for sensing a button being depressed. This limited operating condition may also reduce power consumption and therefore extend the time between re-charging of the battery.
Although these power saving modes save power, the demand for more functionality is increasing the power demands on portable devices. For example, portable media players (“PMPs”) integrate the functions of a cellular phone, PDA, web browser, media player, and a global positioning system (GPS) into one handheld device. All these functions may increase the amount of power used and may decrease the amount of time between re-charging of the battery. This may be troublesome if re-charging is required every day or twice a day.